Japanese Patent Application Laid-Open (JP-A) No. 2010-285019 discloses a vehicle rear portion structure in which both end portions of a connecting member that is disposed substantially horizontally are connected to a quarter inner front reinforcement whose lower end portion is joined to a wheel house outer panel, and to a side body outer extension that extends in the vertical direction along the side edge portion of a back door opening portion (refer to JP-A No. 2010-285019).
Here, when twisting input is applied to the body of the vehicle, the side body outer extension (D pillar, second quarter pillar) deforms so as to fall toward the vehicle vertical direction lower side.
This is a structure in which the connecting member that is disposed substantially horizontally receives, by bending (twisting) deformation, such falling-in deformation of the side body outer extension, and the quarter inner front reinforcement (C pillar, first quarter pillar) receives this bending (twisting) deformation of the connecting member. Accordingly, the connecting member cannot effectively exhibit an effect of suppressing falling-in deformation of the side body outer extension.